saprotrophy

Edge evidence

• saprotrophy enables organic matter decomposition RO:0002327

  Saprotrophic activity breaks down dead organic matter.

  • DOI:10.3389/fmicb.2012.00348 Schimel & Schaeffer support microbial decomposition of organic matter as a central ecosystem process.
• organic matter decomposition consumes dead organic matter biolink:consumes

  Decomposition uses dead organic matter as substrate.

  • DOI:10.1038/nrmicro.2017.87 Fierer supports decomposer activity as a key function of soil microbial communities.
• extracellular exoenzymes converts insoluble organic matter into soluble organic compounds

  Saprotrophs use secreted exoenzymes to hydrolyze/oxidize insoluble dead organic matter into soluble compounds for uptake.

  • DOI:10.1093/ismejo/wrae073 Saprotrophic microbes obtain carbon and energy by hydrolyzing/oxidizing dead organic matter into soluble compounds; insoluble compounds require extracellular enzymes.
• cellulolytic enzyme system depolymerizes cellulose

  Cellobiohydrolases, endoglucanases, and beta-glucosidases act in concert to break down cellulose.

  • DOI:10.1093/jambio/lxac002 Complete degradation of cellulose into glucose involves concerted action of cellobiohydrolases, endoglucanases, and beta-glucosidases.
• cellulose is converted to glucose

  Cellulose depolymerization yields glucose.

  • DOI:10.1093/jambio/lxac002 Complete degradation of cellulose into glucose by the cellulolytic enzyme system.
• carbohydrate-active enzymes (CAZymes) hydrolyzes hemicellulose METPO:2000013

  Extracellular CAZymes hydrolyze hemicellulose polysaccharides at glycosidic bonds.

  • DOI:10.1093/jambio/lxac002 CAZymes act on glycosidic bonds; hemicellulose is targeted by xylanases, beta-mannanases, pectate lyases and related enzymes.
• laccase oxidizes and depolymerizes lignin

  Laccase oxidatively depolymerizes lignin and phenolic substrates via electron transfer.

  • DOI:10.1093/jambio/lxac002 Laccases and peroxidases degrade lignin and the corresponding monomers; laccases modify lignin via hydrogen atom abstraction or electron transfer.
• manganese peroxidase (MnP) catalyzes H2O2-dependent oxidation of lignin

  Manganese peroxidase performs H2O2-dependent oxidative degradation of lignin.

  • DOI:10.1093/jambio/lxac002 Fungal ligninolytic enzymes are mainly manganese peroxidases (MnP) and lignin peroxidases (LiP) catalyzing oxidative reactions dependent on H2O2.
• glucose represses lignocellulolytic gene expression

  Simple sugars/glucose trigger carbon catabolite repression that represses lignocellulolytic gene expression.

  • DOI:10.1093/jambio/lxac002 Glucose is a repressor of fungal cellulolytic enzymes; preferred simple carbon sources cause CreA/Cre1-mediated repression.